clk: pxa: fix one of the pxa RTC clocks

The pxa27x platforms have a single IP with 2 drivers, sa1100-rtc and
rtc-pxa drivers.

A previous patch fixed the sa1100-rtc case, but the pxa-rtc wasn't
fixed. This patch completes the previous one.

Fixes: 8b6d1034

 ("clk: pxa: add missing pxa27x clocks for Irda and sa1100-rtc")
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Link: https://lkml.kernel.org/r/20191026194420.11918-1-robert.jarzmik@free.fr
Signed-off-by: Stephen Boyd <sboyd@kernel.org>